1. Field of the Invention
The disclosed embodiments of the present invention relate to a contact detection scheme, and more particularly, to a detection method and detection device for detecting a plurality of contacts on a touch panel.
2. Description of the Prior Art
In a regular mutual capacitance touch panel, there are two common detection methods. The first detection method is orderly driving all sensing axis on a first dimension (e.g., X axis) on a touch panel and then orderly receiving a sensing signal corresponding each sensing axis on X axis through each sensing axis on a second dimension (e.g., Y axis), and then orderly driving each sensing axis on Y axis and orderly receive a sensing signal corresponding to each sensing axis on Y axis through each sensing axis on X axis. For example, please refer to FIG. 1, which is a schematic diagram of a conventional detection circuit 200 utilized to detect multiple contacts on a touch panel 100. As can be known from the figure, the conventional touch panel 100 has 8 sensing axes X1˜X8 and Y1˜Y8 on X axis and Y axis, respectively, wherein each sensing axis utilizes a multiplexer 210 to determine how the sensing axis is connected to an analog-to-digital converter (ADC) 220 and its working mode through a register device 211. Please note that only one register device is shown in the figure for illustrative purposes. When a driving circuit 250 is used to drive the sensing axis X1, the register device 211 is concurrently configured for utilizing the multiplexer 210 to receive a sensing signal corresponding to the sensing axis X1 on the sensing axis Y1, and then utilizing the ADC 220 to convert the sensing signal into a digital signal and store the digital signal in a storage element (e.g., memory) 230, such that it can be read by a processor (e.g. a micro control unit, MCU) through a control interface 240 later. Next, the conventional method keeps driving the sensing axis X1, and modifies the configuration of the sensing axis Y1 and Y2 in the register device 211 so as to stop the sensing axis Y1 from receiving any receiving signal. After that, the conventional method starts to receive a sensing signal corresponding to the sensing axis X1 on the sensing axis Y2, utilizes the ADC 220 to convert the sensing signal into a digital signal, and then utilizing the processor to read the digital signal via the control interface 240. By the same token, the following sensing signals would be received, stored, and read until all the sensing signals corresponding to the sensing axis X1 on the sensing axis Y1˜Y8 are read by the processor.
In FIG. 1, the conventional detection circuit 200 needs massive configurations and frequent data access for completely detecting a touch event on the touch panel 100. For example, if the detection circuit 200 scan all areas on the touch panel 100 to obtain coordinates of every contact included therein, it would be required to configure the register device 211 and access data through the control interface 240 for at least 8*8*2=128 times. Please refer to FIG. 2, which is a schematic diagram of a preliminary detection of multiple contact events on the touch panel 100, wherein the sensing signal corresponding to Y axis that is received on X axis is denoted as SX, and the sensing signal corresponding to X axis that is received on Y axis is denoted as SY. As can be known from the figure, the sensing signal SX indicates that there are contacts on the sensing axes X2, X3, X6 and X7, and the sensing signal SX indicates that there are contacts on the sensing axes Y2, Y3, Y4, Y5 and Y6. Thus, even a preliminary detection procedure is adapted to narrow down the scan range, the number of configurations and data accesses of the embodiment in FIG. 2 is still equal to at least 4*5*2=40.
Therefore, how to enhance touch event detection efficiency of a touch panel and reduce the number of configurations and data accesses required by the touch event detection is still an issue to be solved in this pertinent field.